Remote Mechanical Switch For Actuating A Power Tool With Particular Microswitch Locating Means

Abstract

A remote mechanical switch for actuating a power tool, such as a router, wherein the mechanical switch is mounted in a control handle connected to the housing of the router. A shielded rod is connected between the housing and the control handle to engage the actuator of a microswitch that is electrically connected to operate the electric motor of the router. The rod places the microswitch in a normally off position. A trigger control is mounted in the control handle and connected to the rod, so that on operation thereof, the rod will be moved away from engagement with the microswitch to cause the same to be actuated.

Description

BACKGROUND OF THE INVENTION

Heretofore, in the prior art, some early power tools such as routers have used toggle switches connected to the motor housing to operate the router. However, since control of the router is accomplished by one or more usually two handles, it is inconvenient and may prove dangerous for the operator to remove one hand from the handle while turning the router on or off. Other routers have avoided this by using a trigger-actuated switch mounted directly in one of the handles, thus making it easier for the operator to control the on or off operation of the tool. This has the disadvantage of requiring additional electric line and associated connections, sometimes in limited space. Furthermore, with the increasing popularity of double insulated tools, providing a second barrier for the external electric line would be both troublesome and costly.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved mechanical switch for a power tool such as a router which overcomes the prior art disadvantages; which is simple, economical and reliable; which has a control switch mounted in a control handle to actuate a microswitch mounted in the motor housing through a rod; which uses a rod having a dielectric shield thereon between the control handle and the motor housing; which uses a hold-down finger formed in the end cap to keep the microswitch in position; and which uses locater pins extending into a recess in the microswitch on the one side and a hold-down finger pressing upon the microswitch on the other side to hold the same in mounted position.

Other objects and advantages will be apparent from the following description of one embodiment of the invention, and the novel features will be particularly pointed out hereinafter in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention is illustrated in the accompanying drawings in which:

FIG. 1 is a front elevational view of a portable electric router embodying the present invention;

FIG. 2 is a partial top plan view of the router of FIG. 1 with parts cut away to show the microswitch and rod of the present invention;

FIG. 3 is an elevational view, taken along lines 3--3, looking into the control handle to see the trigger control and rod in position corresponding to the off position of the motor;

FIG. 4 is a side elevational view looking into the half of the handle and showing the mechanical switch in actuated position, wherein the microswitch is in the on position;

FIG. 5 is a top plan view, partly in section, taken along line 5--5 showing the lock button for the trigger control.

DESCRIPTION OF THE INVENTION

A router, designated generally as 20, is illustrated in FIGS. 1 and 2 as having a stationary base 22, the upper portion of which is in the form of a cylindrical sleeve 24. The sleeve 24 has two downwardly extending diametrically opposed leg portions 26 which terminate in a flat flanged portion 28 that is adapted to contact the work itself, or to receive a nonmetallic subbase 30 suitable for sliding over the work. A large aperture 32 is provided between the legs 26 and flange 28 through which to observe the cutting of the work by a suitable tool bit (not shown) secured in a collet 36 by a nut 38.

Secured to the base 22 on the outside of one leg 26 is a handle 40, and on the other leg 26 is a control handle 42. A trigger control 44 shown in FIGS. 3 and 4 is mounted in the control handle 42 to provide for natural two-hand guiding of the router 20 with the trigger control always under the operator's finger and available for instant control.

A motor housing 46 is adapted to telescope within the base 22 for vertical sliding motion relative thereto. An insulated end cover 48 surmounts the motor housing 46 and is adapted to receive a power cord 50 and to hold down a microswitch 52 mounted at the upper end of the motor housing 46.

A series commutator electric motor 54 is connected in series with a power cable 50 and the microswitch 52, and is mounted within the motor housing 46. The motor 54 has a stator core 56, and brush and brush holders 58 arranged in conventional fashion. A rotor 60 with a commutator 62 is mounted on an armature shaft 64 journaled in bearings 66 and 68. A fan 70 carried by the shaft 64 provides ventilation for the motor by drawing air in through apertures 72 formed in the end cover 48 and exhausting it through apertures 74 in the lower end of the motor housing 46 where it is instrumental in blowing chips away from the bit.

The microswitch 52 as best illustrated in FIG. 4, sits upon a ledge 76 formed at one end of the motor housing 46. The microswitch has two spaced apertures 78 into which a locater pin 80 formed integrally upon the ledge 76 will extend upwardly to position the microswitch. A hold-down finger 82 is formed integrally with the end cover 48 and extends downwardly with the lower tip covered by a cushion 84. After the microswitch 52 is placed upon the pins 80 connecting the cover 48 to the motor housing 46, will cause the hold-down finger to engage the top of the microswitch 52 to positively position the same at a predetermined fixed point upon the ledge 76. The microswitch 52 has an actuator 86 which is depressed to open the circuit corresponding to the off position, and is spring biased to project outwardly from the switch 52 to complete the circuit corresponding to the on position. FIGS. 2 and 3 show the microswitch 52 in an off position, while FIG. 4 shows the microswitch in an on position.

A rod 88 is connected between the trigger control 44 and the actuator 86 of the microswitch 52 to cause the same to be actuated. The rod 88 is encased within a shield 90 having a grommet 92 connect one end of the shield to the control handle 42 and a grommet 94 connect the other end of the shield 90 to one side of the end cover 48 exactly opposite the microswitch 52, as is illustrated in FIGS. 2 and 4.

The trigger control 44 pivots upon a pin 96 connected between the halves of the control handle 42. The forward portion 98 of the trigger control 44 will be engaged by the operator's finger to be pivoted about the pin 96. A connecting arm 100 extends along the opposite side of the pin 96 to receive the rod 88 which passes therethrough. The rod 88 is held in position upon the control arm by a spring 102 which has one end rest upon a connecting hub 104 secured to the rod 88 by a set screw 106, and the other end seated within a recess 108 of the control arm 100. The spring acts to bias the trigger control 44 in the outward position which corresponds to the microswitch 52 being in the off position. A second spring 110 is connected within the grommet 94 and entrapped therein by an enlarged button 112 affixed to the outer end of the rod 88. The button 112 slides within the shield 90, and as shown in FIGS. 2 and 3, when the trigger control 44 is unactuated, the button 112 will be positioned exactly over the actuator 86 to depress the same, thus causing the microswitch 52 to be in the off position. The length of the rod 88 is controlled so that simultaneously with the button 112 engaging the microswitch 52, the lower end 114 of the front portion 98 of the trigger control 44 will rest upon the lower encasement 116 which encloses the front portion 98 of the trigger control 44. The top of the front portion 98 of the trigger control 44 is enclosed by an upper encasement 118.

The trigger control 44 provides for the remote actuation of the microswitch 52. This is beneficial from the point of view of double insulated tools wherein an extra electric line is not required to extend from the housing to the control handle as was necessary in prior art devices. Also, the connection of the shielded rod 120 which is formed by a combination of the rod 88 and the shield 90 is much simpler, more reliable and less costly than the equivalent electric line connection would have been.

The operator can actuate the router 20 at any time by depressing the front portion 98 of the trigger control 44 which produces the pivotal action about pin 96 and compresses the springs 102 and 110, to pull the rod 88 and the connected button 112 away from the actuator 86 of the microswitch 52. Removal of the button 112 permits the actuator 86 to extend outwardly from the microswitch 52 to place the same in the on position. In order to deactivate the router 20, the operator releases his finger from the front portion 98 of the trigger control 44. This results in the springs 102 and 110 respectively causing the trigger control 44 to pivot outwardly and the button 112 to depress the actuator 86.

There will be times when the operator wants to keep the router running for extended periods and to accomplish this, a lock button 122 illustrated in FIG. 5 is provided. The lock button 122 has an enlarged head 124 which extends from the handle 42 to be engaged by the operator. The head 124 slides within a recess 126 formed within the handle 42. A spring 128 is entrapped within the recess 126 to engage the bottom at one side and at the other side urge the head 124 outwardly. A shaft 130 extends from the head 124 to pass through a small hole formed in the bottom of the recess 126 and has an enlarged tip to prevent removal of the lock button 122 from the recess 126. The trigger control 44 has an aperture 132 extending therethrough parallel to the pin 96. On the inner side of the aperture 132, a flange 134 is formed adjacent the lock button 122. Upon the trigger control 44 being depressed as shown in FIGS. 4 and 5, the lock button 122 may also be depressed to enter the aperture 132, whereby the enlarged tip will catch upon the corner of the flange 134 and under the urging of the spring 128 hold the trigger control 44 in depressed position. Release of the lock button 122 is accomplished by merely depressing the trigger control 44 slightly to remove the caught tip of the shaft 130 which springs back into position.

It will be understood that the term "microswitch" has been used throughout the patent application in its broadest sense and is intended to include miniature snap action switches or any other types of switches whether miniature or regular size which fit or could be adapted to be mounted within the end cover 48. Accordingly, though microswitch 52 is of the snap action type, it could readily be replaced for example by a slide action or toggle switch which would likewise be controlled in the "on" or "off" position through the movement of the rod 88 responsive to operator actuation of the trigger control 44.

It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention.

Claims

Having thus set forth the nature of the invention, what is claimed herein is:

1. In a router having a mounting assembly for an electric switch actuated by a remote mechanical switch mounted in a control handle of a housing of a router, the router having an electric motor mounted in the housing, the motor electrically connected to be operated responsive to the electric switch, the combination of:

a. an actuator means projecting from the electrical switch, and having an "on" position and an "off" position,

b. a rod connected between the housing and the control handle, normally to engage the actuator means of the switch to urge the same to remain in the off position,

c. a trigger control for the mechanical switch mounted in the control handle, and connected to the rod therein,

d. an end cover connected to the housing remote from the handle,

e. the switch carried at the end of the housing under the end cover,

f. the rod connected to extend through the end cover in a predetermined location adjacent the switch to engage the actuation means of the switch to cause the switch normally to be in the off position,

g. a switch holding means formed in the end cover to hold the switch in a predetermined position permitting the rod to be in aligned contact with the actuator means of the switch, and

h. the trigger control operatively actuatable to shift the rod and cause the actuator means into the on position to cause the electric switch to actuate the motor.

2. The combination claimed in claim 1 wherein:

a. the electrical switch defines a microswitch,

b. the actuator means defines a button spring biased outwardly in a normally on position,

c. the rod is normally engaged with the button to depress the button into an off position, and

d. the trigger control is operated to move the rod away from the button to permit the button to shift into the on position whereby the microswitch is operated to actuate the motor.

3. The combination claimed in claim 2 wherein:

a. the switch holding means defines a hold-down finger,

b. positioning means formed on the end of the housing to locate the microswitch in a predetermined position, and

c. the hold-down finger, on connection of the end cover to the housing, to press the microswitch into engagement with the said positioning means.

4. The combination claimed in claim 3 wherein:

a. a recess is formed in the microswitch,

b. the positioning means defines a locator pin,

c. a locator pin projects upwardly from the end of the housing adjacent the end cover,

d. the locator pin is disposed in the recess upon mounting the microswitch in the housing, and

e. the hold-down finger presses the microswitch toward the locator pin upon the end cover being connected to the housing.